Fuel blends

ABSTRACT

There is provided a diesel fuel blend comprising one or more commercially available diesel fuels; ethanol and a coupling agent.

FIELD OF THE INVENTION

The invention relates to fuel blend compositions including diesel fueland alcohol.

BACKGROUND OF THE INVENTION

In this specification, where a document, act or item of knowledge isreferred to or discussed, this reference or discussion is not to betaken as an admission that the document, act or item of knowledge or anycombination thereof was at the priority date:

-   -   (a) part of common general knowledge; or    -   (b) known to be relevant to an attempt to solve any problem with        which this specification is concerned.

Diesel oil, due to its cost and availability, continues to be thebackbone for industry around the world being the principal fuel for usein truck, ships, trains, some cars and other automotive equipment anddifferent stationary types of engines.

It is recognised that the combustion of diesel fuel in engines can behazardous to the environment. In particular, the partial combustion ofdiesel fuel to carbon-based particulates, hydrocarbons and carbonmonoxide creates noxious black exhaust gases while the additionalproblem of nitrogen oxide production adds to the pollution. This isparticularly observable in trucks and other automotive vehicles wherenoxious black exhaust gases can be seen as they are released from thevehicle exhaust into the environment.

Attempts have been made over the years to address the environmentalconcerns associated with exhaust fumes from engines by using alcoholssuch as methanol or ethanol as fuels. Such attempts, for instance, haveestablished that 15% ethanol and 85% diesel oil provides a fuel ofacceptable burning capacity without the necessity of modifying existingdiesel engines.

The problem with using ethanol or methanol as a fuel in conjunction withdiesel oil is that ethanol and methanol are immiscible with diesel oilwithin the normal range of operating temperatures, that is, they cannotbe uniformly mixed or blended into one phase without rapid separationinto their component parts.

One attempt to address the immiscibility problem involved mixing dieselfuel, a C3 (excluding n-propanol)-C22 organic alcohol and either (i)ethanol and/or n-propanol or (ii) a mixture of two or more of methanol,ethanol and n-propanol. Another attempt tried mixing diesel fuel, up to20% ethanol or n-propanol and up to 15% of a fatty acid and/or organicester.

However the presence of a significant water content may cause separationof the alcohol and diesel fuel. Water can enter into the fuel in anumber of ways. These include (i) absorbing water from the air, (ii) thealcohol often having some intrinsic water content, and (iii) diesel fuelpicking up water from the refinery pipes which are usually flushed withwater.

Water also forms a constant boiling azeotrope with ethanol. Furtherattempts to remove the water fail by distillation. Even if substantiallydehydrated ethanol is prepared, it is very hygroscopic and will quicklyabsorb moisture from the atmosphere unless subjected to special storagetechniques.

One attempt to address the water content problem involved the use of asurfactant system comprising N, N-dimethylamine and a long chain fattyacid substance in a hybrid fuel microemulsion containing diesel fuel,water and alcohol. These trials further concluded that the advantageprovided by N,N-dimethylamine could not be extrapolated to all aminecompounds because in a comparative trial 2-amino-2-methyl-1-propanol wassubstituted for N,N-dimethylamine and the substituted formulations werenot water tolerant to the same low temperatures.

A second attempt involved using an ethoxylated fatty alcohol and/or itsreaction product with an amide as a stabilising additive. A thirdattempt involves using a polymeric fuel additive formed by reactingtogether an ethoxylated alcohol and a fatty alkanolamide.

There is therefore a need for fuel blends which are more water tolerant,especially at lower temperatures.

SUMMARY OF THE INVENTION

It has been found that diesel fuel and ethanol blends may be preparedwhich are more water tolerant.

According to a first aspect of the invention there is provided a dieselfuel blend comprising:

-   -   (a) greater than about 65% of one or more diesel fuels;    -   (b) up to about 20% v/v of ethanol; and    -   (c) up to about 15% v/v of a coupling agent comprising:        -   (i) greater than about 60% w/w 2-ethylhexanol (also called            iso-octanol);        -   (ii) from 10 to 40% w/w of one or more fatty alkanolamides;            and        -   (iii) up to about 10% w/w of one or more fatty acids.

The diesel fuel suitable for use in this invention is any essentiallypetroleum-based fuel which is suitable for use in a diesel engine.

The sources of ethanol to be used in the invention may range fromcommercially available rectified spirit which typically has 5% waterthrough to absolute ethanol. More preferably, the ethanol will be superdry having less then 0.2% water.

Those skilled in the art will be aware of suitable fatty alkanolamideswhich may be used. The fatty alkanolamide may be derived from primary orsecondary alkanolamines. Examples of suitable alkanolamines includeethanolamine, diethanolamine, diglycolamine, isopropanolamine anddiisopropanolamine. The fatty acid portion is preferably selected fromthe C8 to C20 saturated or unsaturated fatty acids and may be derivedfrom natural vegetable origins (e.g. coconut, canola, soybean), animalorigins (e.g. tallow or lard) or synthetic origins. Preferably, thefatty alkanolamide is oleyl diethanolamide or coconut diethanolamide.

Those skilled in the art will be aware of suitable fatty acids which maybe used. The fatty acid is preferably selected from the C8 to C20saturated or unsaturated fatty acids and may be derived from naturalvegetable origins (e.g. coconut, canola, soybean), animal origins (e.g.tallow or lard) or synthetic origins. Preferably the fatty acid iscommercially available oleic acid or low rosin tall oil.

According to a second aspect of the invention, there is provided acoupling agent for use in fuel blends comprising diesel fuel andethanol, the coupling agent comprising:

-   -   (i) greater than about 60% w/w 2-ethylhexanol (also called        iso-octanol);    -   (ii) from 10 to 40% w/w of one or more fatty alkanolamides; and    -   (iii) up to about 10% w/w of one or more fatty acids.

It has further been found that alternative diesel fuel and ethanolblends may be prepared which are more water tolerant.

According to a third aspect of the invention there is provided a dieselfuel blend comprising:

-   -   (a) greater than about 65% v/v of one or more diesel fuels;    -   (b) up to about 20% v/v of ethanol; and    -   (c) up to about 15% of a coupling agent comprising:        -   (i) greater than about 60% w/w of one or more alkyl esters            of fatty acids;        -   (ii) from 10 to 40% w/w of one or more fatty alkanolamides;            and (iii) up to about 10% w/w of one or more fatty acids.

Those skilled in the art will be aware of suitable alkyl esters of fattyacids which may be used. The fatty acid portion is preferably selectedfrom the C8 to C20 saturated or unsaturated fatty acids and may bederived from natural vegetable origins (e.g. coconut, canola, soybean),animal origins (e.g. tallow or lard) or synthetic origins. The alkylesters may be derived from C1 to C8 alcohols. Preferably, the alkylester of fatty acids is methyl soyate or methyl canolate.

According to a fourth aspect of the invention, there is provided acoupling agent for use in fuel blends comprising diesel fuel andethanol, the coupling agent comprising:

-   -   (i) greater than about 60%/% w/w of one or more alkyl esters of        fatty acids;    -   (ii) from 10 to 40% w/w of one or more fatty alkanolamides; and    -   (iii) up to about 10% w/w of one or more fatty acids.

Further it has been found that the two alternative formulations may becombined to provide alternative diesel fuel and ethanol blends may beprepared which are more water tolerant.

According to a fifth aspect of the invention there is provided a dieselfuel blend comprising:

-   -   (a) greater than about 65% v/v of one or more diesel fuels;    -   (b) up to about 20% v/v of ethanol; and    -   (c) up to about 15% of a coupling agent comprising:        -   (i) greater than about 60% w/w of one or more alkyl esters            of fatty acids and/or 2-ethylhexanol (also called            iso-octanol);        -   (ii) from 10 to 40% w/w of one or more fatty alkanolamides;            and        -   (iii) up to about 10% w/w of one or more fatty acids.

EXAMPLES

The invention will now be further explained and illustrated by referenceto the following non-limiting examples.

Components

The following components are used in the formulations in the examplesbelow.

2-ethylhexanol Ex Orica, Australia Butyl canolate Ex Victorian ChemicalCompany, Australia Ethanol Anhydrous ethanol ex CSR, Australia Ethyltallowate Ex Victorian Chemical Company, Australia Isooctyl oleate ExClariant, Australia Kerosene Kerosene blue ex Recochem, USA Methylcanolate Ex Victorian Chemical Company, Australia Methyl cocoate ExVictorian Chemical Company, Australia Methyl soyate Ex BF Goodrich, USAor P&G, USA Oleic acid Ex Dragon Chemicals, Australia P878 mineral oilEx Shell Oil, Australia USA Diesel Winter grade ex Exxon, USA Vicamid825 Oleyl diethanolamide ex Victorian Chemical Company, AustraliaVicamid 528 Coco diethanolamide ex Victorian Chemical Company, Australia

Example 1

A coupling agent according to the second aspect of the invention wasprepared as follows:

Component Amount (% w/w) 2-ethylhexanol 80 Vicamid 825 17 Oleic acid 3

The 2% v/v coupling agent was combined with 90% v/v diesel fuel and 8%v/v ethanol to provide a fuel blend according to the first aspect of theinvention. This fuel blend was tested in two Landcruiser 4WD utilityvehicles and one light diesel truck and the engines ran satisfactorily.

Example 2

A blend of ethanol and coupling agent was prepared according to thefourth aspect of the invention as follows:

Component Amount (% w/w) Ethanol 63.7 Methyl soyate 27.5 Vicamid 825 8.0Oleic acid 0.8

10% v/v of the ethanol blend was combined with 90% v/v diesel fuel toprovide a fuel blend according to the third aspect of the invention.Similarly, 15% v/v of the ethanol blend was combined with 85% v/v dieselfuel to provide a fuel blend which satisfactorily ran the diesel (4cylinder 1.5 liter) engine of a Volkswagen “Golf”.

Example 3

Fuel blends according to the third aspect of the invention were preparedand tested for water stability.

Component 3A (ml) 3B (ml) Kerosene 150 150 P878 mineral oil 150 150 USADiesel 400 500 Methyl Soyate 180 100 Ethanol 100 80 Vicamid 825 18 g 18g Oleic acid  2 g  2 g Water stability testing Formulation 1 Formulation2 Overnight in freezer @ −8° C. clear uniform clear uniform 0.5 g wateradded, 2 hours in clear uniform clear uniform freezer at −8° C. Further0.5 g water added, 2 clear uniform 2 layers, cloudy hours in freezer at−8° C. Cloud point of wet product* <−8° C. +5° C. Final water content**(%) 0.19 0.19 *The appearance of the cloud point shows the temperatureat which instability of the formulation occurs. The lower thetemperature of the cloud point evidences greater stability. The cloudpoint has no relevance to engine performance. **Water content in theformulations, as here and later mentioned through the patent, has beenmeasured via the Karl Fischer titration method (D4377 of the ASTM).

These results show that by the addition of the additives the watertolerance of the formulation has been improved.

Example 4

A series of formulations of 20% v/v anhydrous alcohol in USA ‘wintergrade’ diesel oil were prepared and water stability compared.

Formulation Control 4A 4B 4C diesel 80 65 65 65 ethanol 20 20 20 202-ethylhexanol — 9 — — methyl cocoate — — 9 — methyl soyate — — — 9Vicamid 825 — 5.5 5.5 5.5 Oleic acid — 0.5 0.5 0.5

Water stability Control 4A 4B 4C Initial water (%) 0.11 0.09 0.10 0.10Initial cloud point (CP) (° C.) +12 <−8 <−8 <−8 +0.1% water, CP n/a <−8<−8 <−8 Further +0.1% water, CP n/a <−8 <−8 −6 Further +0.1% water, CPn/a <−8 <−8 −3 Further +0.1% water, CP n/a <−8 −5 +2 Further +0.1%water, CP n/a <−8 0 n/a Further +0.1% water, CP n/a <−8 +6 n/a Further+1.0% water, CP n/a <−8 n/a n/a Further +0.2% water, CP n/a −4 n/a n/aFurther +0.1% water, CP n/a +2 n/a n/a Final water (%) 0.11 2.11 0.810.58

These results further show that by the addition of the additives thewater tolerance of the formulation has been improved. Indeed formulation4A is sufficiently robust that those skilled in the art will recognisethat rectified ethanol can be used.

Example 5

A series of formulations of 10% v/v anhydrous alcohol in USA ‘wintergrade’ diesel oil were prepared and water stability compared.

Formulation Control 5A 5B 5C 5D Diesel 90 80 80 80 80 Ethanol 10 10 1010 10 2-ethylhexanol — 6 — — — Methyl soyate — — 6 — — Butyl canolate —— — 6 — Ethyl tallowate — — — — 6 Vicamid 825 — 3.6 3.6 3.6 3.6 Oleicacid — 0.4 0.4 0.4 0.4

Water stability Control 5A 5B 5C 5D Initial water (%) 0.07 0.07 0.070.07 0.07 Initial cloud point (CP) (° C.) +2 <−8 <−8 <−8 <−8 +0.1%water, CP n/a <−8 <−8 <−8 <−8 Further +0.1% water, CP n/a <−8 +7 +11 +7Further +0.1% water, CP n/a <−8 n/a n/a n/a Further +0.1% water, CP n/a<−8 n/a n/a n/a Further +0.3% water, CP n/a <−8 n/a n/a n/a Further+0.1% water, CP n/a +4 n/a n/a n/a Final water (%) 0.07 1.01 0.30 0.300.29

These results further show that by the addition of the additives thewater tolerance of the formulation has been improved. Indeed formulation5A is sufficiently robust that those skilled in the art will recognisethat rectified ethanol can be used.

Example 6

A series of formulations of 5% v/v anhydrous alcohol in USA ‘wintergrade’ diesel oil were prepared and water stability compared.

Formulation Control 6A 6B 6C 6D Diesel 95 90 90 90 90 Ethanol 5 5 5 5 52-ethylhexanol — 3 — — — Isooctyl oleate — — 3 — — Methyl soyate — — — 3— Butyl canolate — — — — 3 Vicamid 825 — 1.8 1.8 1.8 1.8 Oleic acid —0.2 0.2 0.2 0.2

Water stability Control 6A 6B 6C 6D Initial water (%) 0.04 0.04 0.040.04 0.04 Initial cloud point (CP) (° C.) <−8 <−8 <−8 <−8 <−8 +0.1%water, CP +37 <−8 +33 +25 +26 Further +0.1% water, CP n/a <−8 n/a n/an/a Further +0.1% water, CP n/a −6 n/a n/a n/a Further +0.1% water, CPn/a +28 n/a n/a n/a Final water (%) 0.16 0.39 0.16 0.16 0.16

These results further show that by the addition of the additives thewater tolerance of the formulation has been improved.

Example 7

A series of formulations of 10% v/v anhydrous alcohol in USA ‘wintergrade’ diesel oil were prepared using coco diethanolamide and waterstability compared.

Formulation Control 7A 7B 7C Diesel 90 80 80 80 Ethanol 10 10 10 10Methyl soyate — 6 6 6 Vicamid 528 — 3.6 3.3 3.0 Oleic acid — 0.4 0.7 1.0

Water stability Control 7A 7B 7C Initial water (%) 0.07 0.05 0.06 0.06Initial cloud point (CP) (° C.) +2 −5 <−8 <−8 +0.1% water, CP n/a +11 −1<−8 Further +0.1% water, CP n/a n/a n/a +16 Further +0.1% water, CP n/an/a n/a n/a Final water (%) 0.07 0.17 0.17 0.39

These results further show that by the addition of the additives thewater tolerance of the formulation has been improved.

Example 8

A formulation of 10% v/v anhydrous alcohol in USA ‘winter grade’ dieseloil was prepared using methyl canolate and water stability compared.

Formulation Control 8A Diesel 90 80 Ethanol 10 10 Methyl canolate — 6Vicarmid 825 — 3.6 Oleic acid — 0.4

Water stability Control 8A Initial water (%) 0.07 0.06 Initial cloudpoint (CP) (° C.) +2 <−8 +0.1% water, CP n/a <−8 Further +0.1% water, CPn/a +11 Further +0.1% water, CP n/a n/a Final water (%) 0.07 0.37

These results further show that by the addition of the additives thewater tolerance of the formulation has been improved.

Example 9

A formulation of 15% v/v anhydrous alcohol in USA ‘winter grade’ dieseloil was prepared using a blend of additives and water stabilitycompared.

Formulation Control 9A Diesel 85 72 Ethanol 15 15 2-Ethylhexanol — 4Methyl soyate — 4 Vicamid 825 — 4.5 Oleic acid — 0.5

Water stability Control 9A Initial water (%) 0.09 0.08 Initial cloudpoint (CP) (° C.) +6 <−8 +0.1% water, CP n/a <−8 Further +0.1% water, CPn/a <−8 Further +0.1% water, CP n/a <−8 Further +0.1% water, CP n/a <−8Further +0.3% water, CP n/a −5 Further +0.1% water, CP n/a +6 Finalwater (%) 0.09 1.01

These results further show that the water tolerance of the formulationhas been improved. Indeed formulation 9A is sufficiently robust thatthose skilled in the art will recognise that rectified ethanol can beused.

The word ‘comprising’ and forms of the word ‘comprising’ as used in thisdescription do not limit the invention claimed to exclude any variantsor additions.

Modifications and improvements to the invention will be readily apparentto those skilled in the art. Such modifications and improvements areintended to be within the scope of this invention.

1. A diesel fuel blend comprising one or more diesel fuels, ethanol, anda coupling agent, wherein the amounts of the one or more diesel fuels,ethanol and coupling agent in the blend are: (a) greater than about 65%of the one or more diesel fuels; (b) up to about 20% v/v of the ethanol;and (c) up to about 15% v/v of the coupling agent; wherein ethanol andthe coupling agent are present in the blend, and the coupling agentcomprises: (i) greater than about 60% w/w 2-ethylhexanol; (ii) from 10to 40% w/w of one or more fatty alkanolamides; and (iii) up to about 10%w/w of one or more fatty acids; wherein one or more fatty acids arepresent in the coupling agent.
 2. A diesel fuel blend according to claim1 wherein the one or more alkanolamides are derived from ethanolamine,diethanolamine, diglycolamine, isopropanolamine and diisopropanolamine.3. A diesel fuel blend according to claim 1 wherein the one or morealkanolamides are derived from C8 to C20 saturated or unsaturated fattyacids of natural or synthetic origin.
 4. A diesel fuel blend accordingto claim 1 wherein the alkanolamide is oleyl diethanolamide.
 5. A dieselfuel blend according to claim 1 wherein the one or more fatty acids areselected from the group consisting of C8 to C20 saturated or unsaturatedfatty acids of natural or synthetic origin.
 6. A diesel fuel blendaccording to claim 1 wherein the fatty acid is oleic acid.
 7. A couplingagent for use in fuel blends comprising diesel fuel and ethanol, thecoupling agent comprising: (a) greater than about 60% w/w2-ethylhexanol; (b) from 10 to 40% w/w of one or more fattyalkanolamides; and (c) up to about 10% w/w of one or more fatty acids;wherein one or more fatty acids are Present in the coupling agent.
 8. Adiesel fuel blend comprising one or more diesel fuels, ethanol, and acoupling agent, wherein the amounts of the one or more diesel fuels,ethanol and coupling agent in the blend are: (a) greater than about 65%v/v of the one or more diesel fuels; (b) up to about 20% v/v of theethanol; and (c) up to about 15% of the coupling agent; wherein ethanoland the coupling agent are present in the blend, and the coupling agentcomprises: (i) greater than about 60% w/w of one or more alkyl esters offatty acids; (ii) from 10 to 40% w/w of one or more fatty alkanolamides;and (iii) up to about 10% w/w of one or more fatty acids; wherein one ormore fatty acids are present in the coupling agent.
 9. A diesel fuelblend according to claim 8 wherein the one or more alkyl esters of fattyacids are derived from C8 to C20 saturated or unsaturated fatty acids ofnatural or synthetic origin.
 10. A diesel fuel blend according to claim8 wherein the one or more alkyl esters of fatty acids are derived fromC1 to C8 alcohols.
 11. A diesel fuel blend according to claim 8 whereinthe one or more alkanolamides are derived from ethanolamine,diethanolamine, diglycolamine, isopropanolamine and diisopropanolamine.12. A diesel fuel blend according to claim 8 wherein the one or morealkanolamides are derived from C8 to C20 saturated or unsaturated fattyacids of natural or synthetic origin.
 13. A diesel fuel blend accordingto claim 8 wherein the alkanolamide is oleyl diethanolamide.
 14. Adiesel fuel blend according to claim 8 wherein the one or more fattyacids are selected from the group consisting of C8 to C20 saturated orunsaturated fatty acids of natural or synthetic origin.
 15. A dieselfuel blend according to claim 8 wherein the fatty acid is oleic acid.16. A coupling agent for use in fuel blends comprising diesel fuel andethanol, the coupling agent comprising: (a) greater than about 60% w/wof one or more alkyl esters of fatty acids; (b) from 10 to 40% w/w ofone or more fatty alkanolamides; and (c) up to about 10% w/w of one ormore fatty acids; wherein one or more fatty acids are present in thecoupling agent.
 17. A diesel fuel blend comprising one or more dieselfuels, ethanol, and a coupling agent, wherein the amounts of the one ormore diesel fuels, ethanol and coupling agent in the blend are: (a)greater than about 65% v/v of the one or more diesel fuels; (b) up toabout 20% v/v of the ethanol; and (c) up to about 15% of the couplingagent; wherein ethanol and the coupling agent are present in the blend,and the coupling agent comprises: (i) greater than about 60% w/w of oneor more alkyl esters of fatty acids, 2-ethylhexanol, or a combination ofone or more of said alkyl esters of fatty acids and 2-ethylhexanol; (ii)from 10 to 40% w/w of one or more fatty alkanolamides; and (iii) up toabout 10% w/w of one or more fatty acids; wherein one or more fattyacids are present in the coupling agent.